3 Answers
3

Shift does nothing for the miniature effect, though it may help with a particular composition.

Tilt does the work, by simulating a much smaller depth of field. For this you need a relatively "flat" subject, e.g. the ground as seen from an elevated position. This is so the parts of the ground in front and behind the focal plane are thrown out of focus more than they would be with a conventional lens.

If you were to try and get the effect with a non flat subject, like corridor, it would not work at all, as the floor would appear to have a shrunk depth of field, as would the ceiling, but in focus part of the ceiling would be at entirely the wrong distance from camera, as the focal plane is tilted over. And the walls would look funny too as the area in focus would run diagonally.

Getting high up helps a lot, and ensures your scene is more like the flat example. If you are low down in a built up area, the buildings become the walls, and the sky becomes the ceiling of the corridor and the effect is ruined.

In almost all cases you want to have the tilt axis horizontal in the final image (so if it's a landscape shot tilt should be about the horizontal axis of the camera).

The shift axis should be aligned with the tilt. This is because you may also want to shift minimise the amount of sky/avoid having the horizon in the image.

Including the horizon doesn't alter the effect, though it is a dead giveaway that it is a fake miniature not a real macro shot (when was the last model railway you saw that stretched all the way to the horizon?)

The amount of tilt depends on taste. Obviously if there is very little tilt you wont get the apparent reduction in depth of field. If there is too much, there wont be enough in focus to make a coherent image.

The only thing I would say for tilting and focusing is that you should pick out a subject, one person or object and make sure the focus plane intersects that point.

The points Matt Grum lists are all good, however the degree of tilt of the plane of focus is controlled by the focus distance rather than the tilt setting on the lens as seen in the animation on this page (although it shows the back moving rather than the lens), having the lens focused at infinity will cause the centerline of the in-focus wedge to be parallel to the lens axis. The tilt setting controls how var away from the center of the lens axis the point that the plane of focus tilts around is.

This document provides a good overview of the two rules that control the position and orientation of the plane of focus when using a tilt-shift lens.

As Matt mentions you will want the tilt and shift axes to be parallel to each other both to enable be able to add to the apparent downward angle of the camera and to be able to avoid dead giveaways of the fakeness of the image.

Ideally the lens would be tilted down with respect to the ground in the scene in order to have the direction of tilt match that which would be expected of a real picture of a miniature scene (closer to camera at the bottom, farther away at the top). This is likely to be very difficult if taking a picture of a large area since the tiny degree of tilt required to get the plane of focus to intersect the visible image at sufficient distance from the camera is effectively impossible to set (the higher the degree of tilt the closer to the camera the point around which the plane of focus pivots is).

In this situation you may have to tilt the lens up with respect to the scene to be able to place the in focus area of the image in an appropriate place. If you do this then you would need to be careful to place it in a location such that tall structures/trees that are closer to the camera than the point where the plane intersects the ground do not have their tops in focus.

Since the tilt and shift axes need to be parallel you will need to use the rotation of the lens to make the tilt plane parallel to the ground in the image.